Atlanta got its first tropical storm warning in city history Sunday, with schools closing and the nation’s busiest airport weighing a possible shutdown.

Mayor Kasim Reed urged residents to prepare for the worst.

“Don’t be fooled that this storm cannot hurt you. Don’t go out and play in it,” he said. “We urge everyone to stay indoors and stay safe as we make it through this challenging moment.”

Several school districts, Georgia State University in Atlanta and the University of Georgia in Athens announced there would be no classes Monday.

Hartsfield-Jackson Atlanta International Airport was open Sunday. Airport spokesman Andrew Gobeil said Friday that officials were in close contact with the FAA and would monitor the path of Hurricane Irma.